For example, this gives a clear overview of the temperature trend in the 15 day period. (London 12z ECMWF ensemble data).

https://charts.ecmwf.int/streaming/20251221-2140/34/render-worker-commands-c479f5985-sfbxl-6fe5cac1a363ec1525f54343b6cc9fd8-eain46h1.png 

GEFS:

Differences between both, but there is a trend at least for a significant Euro cool down, with the AI model showing an encouraging trend for a more traditional cold pattern over the NE of Europe, which may have consequence down the line (if the high stays to the north!)

Tonight's national and local forecasts on the BBC seem to indicate temperatures close to average.

Yes I suspect it will, based on most output, be just a little below average after the next few days. Something that we have yet to see this winter. Nothing too extreme and generally quite settled compared with the start of winter. Colder options are available and the medium to longer term trends are worth watching.

Yes - the Control is also a thing of beauty! www.wetterzentrale.de/maps/GFSC00EU12_6_2.png

if only this were to verify! I hope it doesn’t just downgrade via a thousand cuts like the Xmas snow event - that seemed so nailed on for so long, but I am enjoying the eye candy! 

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=2&run=12&time=276&lid=C00&h=0&mv=0&tr=6#mapref 

No, it’s not. 

nowhere near active enough. 

But no: it’s as if there is a force field preventing them getting on shore. It is probably just GW and the high SSTs, but this seems  very odd that we remain in -5 territory despite the cold air upwind being abundant!

Hope this link works!

A pattern change pretty bang on the change in seasons. 

I’m sure most will enjoy a drier, chillier picture as winter begins.

https://weather.metoffice.gov.uk/learn-about/weather/seasons/winter/when-does-winter-start 

Ok -  can you tell that from this chart? It’s quite a pronounced kink in the isobars.

Would beg to differ. The chart posted by BBlake shows a very cold air mass moving down over warm waters. That potentially could trigger both snow and thunder. The pattern itself does not need to 'look' that active. 

Interesting fact about thunder snow. It is very often heard only over a relatively small area as the falling snow can absorb and dampen the sound greatly. So if thunder is heard during a snow squall, it is very likely that the lightning strke was very close by. 

The forecasts I saw said colder by Xmas Eve and several degrees below average for Xmas Day and Boxing Day in the East/South East.  That is in line with the model output.

Lets see if the morning brings a miracle and reduced data over weekend is a real thing or myth

So, what happens next? ECM-46 is still rock-solid on a prolonged colder than average spell, peaking over the New Year week but lingering well beyond - indeed, there's blue throughout down here, and even on week 4 - the least cold of the weeks - there's blue shading over southern and western parts.

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202512210000&projection=opencharts_europe&valid_time=202601050000 

Note that there are a few options with the cold - it could be the mean of a -9 and +3 anomaly, say, or it could be the mean of a -4 to -2 anomaly - we can't see that detail, annoyingly.

It does look like there'll be a relatively benign spell once the easterly waft clears away, with the potential (just potential) for some really cold temperatures, especially "up north", should skies stay clear under the ridge. 

After that is when it gets interesting, which tallies with that New Year week forecast from the ECM-46. It's not very exciting down here to be frank, but if I were further north I'd be keeping a keen eye on developments, as the potential is there for a snowy spell... and this time it wouldn't go over France, either. 

https://ukwct.org.uk/weather/enswatch5.jpg 

I'd say a 30% chance is actually a fairly good guide atm. 

Can we keep the northern blocking going through January as the ECM 46 suggests? Is the ECM 46 to be trusted? Not normally no, but as ever we live in hope.

AIFS is pick of the bunch the morning. Later on it shows our UK high potentially linking with an Artic high. This could have serious consequences into Jan for prolonged and severe cold.